Modular layer horizontal storage module and methods of manufacturing same

ABSTRACT

A horizontal storage module (HSM) assembly generally includes a base portion including a plurality of segments that are vertically layered on top of each other and a lid portion. A method of constructing an HSM assembly generally includes forming a plurality of segments for the base portion of the HSM assembly, and vertically stacking the segments.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.61/682,696, filed Aug. 13, 2012, the disclosure of which is expresslyincorporated by reference herein in its entirety.

BACKGROUND

Horizontal storage modules (HSMs) are typically used for the dry storageand containment of radioactive materials in ventilated canister storagesystems at reactor or other storage sites. Previously designed HSMs aregenerally manufactured from reinforced concrete as a single base unitwith an attachable lid. These HSMs may have dimensions of about 18-20feet in height, by about 8-10 feet in width and about 20-22 feet inlength. The weight of these single base unit HSMs can be around 320,000lbs (unloaded).

HSM units are typically constructed at a manufacturing site in twopieces (base and lid), then the pieces are shipped to a reactor orstorage site for use. Due to shipping regulations, single base unit HSMsmust be shipped by rail or barge because they are too heavy and toolarge to be shipped by truck. In view of the size and weight, theshipping costs for such large, heavy single base unit HSMs have becomevery high and, in some cases, cost prohibitive.

To solve the shipping problem, there exists a need for modular HSMs thatcan be shipped in parts, then easily reassembled on site. However,designers have been hesitant to develop modular HSMs in the past becauseof concerns regarding inferior structural integrity, thereby requiringregular maintenance checks and causing inconvenience to the HSM users.Therefore, there exists a need for modular HSMs having improvedstructural integrity. Embodiments of the present disclosure are directedto fulfilling this and other needs.

SUMMARY

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This summary is not intended to identify key features ofthe claimed subject matter, nor is it intended to be used as an aid indetermining the scope of the claimed subject matter.

In accordance with one embodiment of the present disclosure, an HSMassembly is provided. The assembly generally includes a base portionincluding a plurality of segments that are vertically layered on top ofeach other, and a lid portion.

In accordance with another embodiment of the present disclosure, amethod of constructing an HSM assembly is provided. The method generallyincludes forming a plurality of segments for the base portion of the HSMassembly, and vertically stacking the segments.

In accordance with any of the embodiments described herein, the baseportion may include at least first and second segments.

In accordance with any of the embodiments described herein, the baseportion may include at least first, second, and third segments.

In accordance with any of the embodiments described herein, theplurality of segments may be substantially similar in at least one ofsize, shape, and weight.

In accordance with any of the embodiments described herein, adjacentsegments may be attached to one another using a vertical attachmentsystem.

In accordance with any of the embodiments described herein, the verticalattachment system may include a plurality of vertically oriented holesin the sidewalls of adjacent segments, and ties connecting such holes.

In accordance with any of the embodiments described herein, theplurality of segments may be made from reinforced concrete.

In accordance with any of the embodiments described herein, theplurality of segments may include shear keys between segments.

In accordance with any of the embodiments described herein, adjacentsegments may be attached to one another using only a vertical attachmentsystem.

In accordance with any of the embodiments described herein, theplurality of segments may be formed in a single form.

In accordance with any of the embodiments described herein, the firstsegment may be poured and allowed to harden, and the second segment maybe poured on the hardened first segment.

In accordance with any of the embodiments described herein, the secondsegment is allowed to harden, and the third segment is poured on thehardened second segment.

In accordance with any of the embodiments described herein, theplurality of segments may include bond breakers between adjacentsegments in the form.

In accordance with any of the embodiments described herein, a method ofconstruction may further include vertically attaching adjacent segments.

In accordance with any of the embodiments described herein, a method ofconstruction does not include horizontally attaching adjacent segments.

In accordance with any of the embodiments described herein, theplurality of segments may be stacked using a single lifting fixture.

DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisdisclosure will become more readily appreciated as the same becomebetter understood by reference to the following detailed description,when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is an isometric view of a modular layer horizontal storage module(HSM) assembly in accordance with one embodiment of the presentdisclosure;

FIG. 2 is an exploded view of the modular layer HSM assembly of FIG. 1;

FIG. 3 is a front view of the modular layer HSM assembly of FIG. 1;

FIG. 4 is a side view of the modular layer HSM assembly of FIG. 1;

FIG. 5 is an isometric view of a modular layer HSM assembly inaccordance with another embodiment of the present disclosure;

FIG. 6 is an exploded view of the modular layer HSM assembly of FIG. 5;

FIG. 7 is a front view of the modular layer HSM assembly of FIG. 5;

FIG. 8 is a side view of the modular layer HSM assembly of FIG. 5; and

FIG. 9 is an isometric view of a previously designed HSM.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings, where like numerals reference like elements, is intended as adescription of various embodiments of the disclosed subject matter andis not intended to represent the only embodiments. Each embodimentdescribed in this disclosure is provided merely as an example orillustration and should not be construed as preferred or advantageousover other embodiments. The illustrative examples provided herein arenot intended to be exhaustive or to limit the disclosure to the preciseforms disclosed. Similarly, any steps described herein may beinterchangeable with other steps, or combinations of steps, in order toachieve the same or substantially similar result.

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of exemplary embodiments ofthe present disclosure. It will be apparent to one skilled in the art,however, that many embodiments of the present disclosure may bepracticed without some or all of the specific details. In someinstances, well-known process steps have not been described in detail inorder not to unnecessarily obscure various aspects of the presentdisclosure. Further, it will be appreciated that embodiments of thepresent disclosure may employ any combination of the features describedherein.

Embodiments of the present disclosure are directed to horizontal storagemodule (HSM) assemblies, for example, used for the dry storage andcontainment of radioactive materials in ventilated canister storagesystems having modular constructions, and methods of manufacturing thesame. Referring to FIGS. 1-3, a modular layer HSM assembly 10constructed in accordance with one embodiment of the present disclosureis provided. The modular layer HSM assembly 10 includes a base portion20 having a plurality of segments or layers 22, 24, 26 that can bevertically stacked on top of one another, and a separate lid 28. Suchvertical stacking construction employs a vertical attachment system, asis described in greater detail below.

Referring to FIG. 9, a previously designed single base unit HSM 210 isprovided. Like a modular layer HSM assembly 10, a previously designedHSM 210 is generally manufactured from reinforced concrete. The HSM 210includes a base 220 for receiving a canister C containing radioactivematerials. In that regard, the HSM 210 includes a front entry hole 230,and an internal chamber designed for supporting a container. A shielddoor (not shown) can be used to close the front entry hole 230 of theHSM 210 after a canister C has been received. A lid 228 is manufacturedseparately from the base 220 and placed on top of the base 220 whenassembled on site for use.

Previously designed HSMs 210 are generally designed with enhancedradioactive shielding performance, seismic capabilities, heat rejectioncapabilities, and ruggedness for resisting acts of sabotage. Moreover,previously designed HSMs 210 are fabricated off-site so as to notrequire any major construction at the containment site. Embodiments ofthe present disclosure directed to modular layer HSM assemblies are alsodesigned to meet these criteria.

As a non-limiting example, a standard HSM has a height of about 222inches (18.5 feet), with the base portion having a height of about 178inches (14 feet, 10 inches) and the lid portion having a height of about44 inches (3 feet, 8 inches). Because of these large dimensions, theforming of the concrete forms for the base portion is complex. In thatregard, large metal forms for forming the base portion are heavilystiffened to accommodate the high hydrostatic pressure within the forms.Despite heavy stiffening, deflection problems are often encountered withthese forms as a result of the high hydrostatic pressure in the forms.Moreover, replacement of these forms is expensive as a result of theheavy stiffening required.

Returning to FIGS. 1-4, the modular layer HSM assembly 10 designed inaccordance with one embodiment of the present disclosure has a baseportion 20 having a segmented design. In that regard, the base portion20 includes individual segments 22, 24, 26 that can be verticallystacked on top of one another, and a lid portion 28 is designed andconfigured to stack on top of the base portion 20. In the illustratedembodiment, the base portion 20 is divided into three segments; however,it should be appreciated that any number of segments are within thescope of the present disclosure. For example, the embodiment of FIGS.5-8 includes two segments, as will be described in greater detail below.

In the illustrated embodiment of FIGS. 1-4, the three segments 22, 24,and 26 of the base portion 20 have divisions between segments inhorizontal planes occurring above and below the front entry hole 30.Therefore, the segmentation does not divide the front entry hole 30 orthe internal chamber that is designed to support a container. In oneembodiment of the present disclosure, the segments 22, 24, and 26 aresubstantially similar in at least one of size, shape, and weight. Theterm “substantially” is used herein to be within an acceptable range ofengineering tolerance in the industry. It should be appreciated,however, that other vertical segmentation so that the segments 22, 24,and 26 are not substantially similar in at least one of size, shape, andweight is also within the scope of the present disclosure.

In accordance with one embodiment of the present disclosure, a method ofmanufacturing the segmented base portion 20 will now be described. Likethe previously designed HSM 210, described above, the modular layer HSMassembly 10 is constructed using reinforced concrete that is poured in asingle form. The first segment 22 of the base section 20 is poured intothe form, and allowed to harden. Thereafter, the second segment 24 ofthe base section 20 is poured into the form on top of the hardened firstsegment 22. Subsequently, the third segment 26 is poured into the formon top of the hardened second segment 24. The lid 28 may be formedseparately, or may be formed on top of on top of the hardened thirdsegment 26.

By casting subsequent layers against a hardened previous layer, thejoints are almost invisible when the segments 22, 24, and 26 arereassembled during the assembly of the HSM assembly 10 at the site ofuse. A bond breaker can be applied to each hardened segment before thesubsequent segment is poured to ensure that the segments will separate.This process is called match casting and is widely used in the pre-castindustry.

Other casting techniques may also be used to ensure a good fit betweensegments 22, 24, and 26. For example, the individual segments may becast in separate forms with special attention to dimensional control ofthe matching faces and shear keys.

Because of casting in multiple segments 22, 24, and 26, the hydrostaticpressure in the segments is substantially decreased in a linear relationto the segment height, as compared to a single base unit HSM 210 (asdescribed above and as can be seen in FIG. 9). As the hydrostaticpressure is reduced, the potential for dimensional deviation in thesegments 22, 24, and 26 is significantly reduced. As a non-limitingexample, for a three-segment concept, the hydrostatic pressure in eachsegment may be decreased in a linear relation to segment height to beapproximately ⅓ of the hydrostatic pressure in a comparable single baseunit HSM 210. Likewise, for a two-segment concept, the hydrostaticpressure in each segment may be decreased to be approximately ½ of thehydrostatic pressure in a comparable single base unit HSM 210.

Moreover, the forms for manufacturing the modular layer HSM assembly 10are less expensive and more reliable because they are not required to bestiffened for handling the height requirements of a comparable singlebase unit HSM 210. Although described as using a single form, it shouldbe appreciated that the use of multiple forms for the various differentsegments of the base portion 20 is also within the scope of the presentdisclosure.

After forming, the segments 22, 24, and 26 of the base portions 20 areindividually shipped to the reactor or storage site. Segment shippingsignificantly reduces the size and weight of components shipped, andthereby improves the ease of shipping.

At the user's site, the segments 22, 24, and 26 of the base portion 20can be vertically stacked on top of each other and secured using anattachment system. The segments may be substantially similar to oneanother in size, shape, and placement during assembly; therefore, onelifting fixture can be employed for assembling the various layers of themodular layer HSM, further reducing assembly cost and complexity.

Because the segments 22, 24, and 26 of the base portion 20 verticallystack on top of each other, the modular layer HSM assembly 10 can relyon gravity and friction between the segments to maintain the baseportion 20 construction. In addition to gravity and friction, the baseportion 20 can be further secured with a vertical attachment system, andtherefore, avoids using a horizontal attachment system, such as a posttension system. A modular layer HSM assembly 10 having verticalconnections between segments has more structural integrity than can beseen in modular assemblies that include horizontal attachment systems.

A suitable vertical attachment system may include holes 42 in thesidewalls of the adjacent various segments 22, 24, and 26 that arejoined using ties 44, such as rebar ties, which are then grouted inplace in the holes. The holes 42 may be formed during the moldingprocess, or may be drilled after forming.

In the illustrated embodiment of FIGS. 1-4, the HSM assembly 10 includesseveral ties 44 between adjacent segments 22, 24, and 26. The number ofties required for an HSM assembly may depend on the size of theassembly, the number of segments, and the government certificationtesting for HSM assemblies. In one embodiment, the HSM assembly 10 mayinclude four or more ties between adjacent segments. In anotherembodiment, the HSM assembly 10 may include eight or more ties betweenadjacent segments. In another embodiment, the HSM assembly 10 mayinclude sixteen or more ties between adjacent segments.

It should be appreciated that other vertical attachment systems are alsowithin the scope of the present disclosure, for example, tie plates maybe used as an attachment system. Suitable tie plates may be bolted,welded, embedded, or a combination thereof.

In addition or in the alternative to a vertical attachment system,adjacent segments may include interlocking shear keys, such as recessesand protrusions that match on adjoining surfaces of adjacent segments(see, for example, recess 154 and protrusion 152 in FIG. 6). Such shearkeys prevent any sliding horizontal movement of adjacent segmentsrelative to each other.

Referring now to FIGS. 5-8, an HSM assembly 100 designed in accordancewith another embodiment of the present disclosure will now be described.The HSM assembly 100 of FIGS. 5-8 and the methods for manufacture andassembly are substantially similar to the HSM assembly 10 of FIGS. 1-4,except for differences regarding the number of segments and the divisionlines between segments. Like numerals for like parts are used todescribed the embodiment of FIGS. 5-8.

In the illustrated embodiment of FIGS. 5-8, the modular layer HSMassembly 100 has a base portion 120 having a two-part segmented design.In that regard, the base portion 120 includes individual segments 122and 124 that can be vertically stacked on top of one another, and a lidportion 128 is designed and configured to stack on top of the baseportion 120.

The two segments 122 and 124 of the base portion 120 have a verticaldivision between the segments in a horizontal plane occurring throughthe front entry hole 130 and the internal chamber that is designed tosupport a container.

Like the HSM assembly 10 of FIGS. 1-4, the HSM assembly 100 of FIGS. 5-8includes ties 144 between adjacent segments 122 and 124. The number ofties required for an HSM assembly may depend on the size of theassembly, the number of segments, and the government certificationtesting for HSM assemblies. Adjacent segments 122 and 124 may includeinterlocking shear keys prevent any sliding horizontal movement ofadjacent segments relative to each other. As mentioned above, anexemplary recess 154 and protrusion 152 is shown in FIG. 6.

The principles, representative embodiments, and modes of operation ofthe present disclosure have been described in the foregoing description.However, aspects of the present disclosure which are intended to beprotected are not to be construed as limited to the particularembodiments disclosed. Further, the embodiments described herein are tobe regarded as illustrative rather than restrictive. It will beappreciated that variations and changes may be made by others, andequivalents employed, without departing from the spirit of the presentdisclosure. Accordingly, it is expressly intended that all suchvariations, changes, and equivalents fall within the spirit and scope ofthe present disclosure, as claimed.

The embodiments of the disclosure in which an exclusive property orprivilege is claimed are defined as follows:
 1. An HSM assembly,comprising, (a) a base portion including a plurality of segments thatare vertically layered on top of each other; and (b) a lid portion. 2.The assembly of claim 1, wherein the base portion includes at leastfirst and second segments.
 3. The assembly of claim 1, wherein the baseportion includes at least first, second, and third segments.
 4. Theassembly of claim 1, wherein the plurality of segments are substantiallysimilar in at least one of size, shape, and weight.
 5. The assembly ofclaim 1, wherein adjacent segments are attached to one another using avertical attachment system.
 6. The assembly of claim 5, wherein thevertical attachment system includes a plurality of vertically orientedholes in the sidewalls of adjacent segments, and ties connecting suchholes.
 7. The assembly of claim 1, wherein the plurality of segments aremade from reinforced concrete.
 8. The assembly of claim 1, wherein theplurality of segments include shear keys between segments.
 9. Theassembly of claim 1, wherein adjacent segments are attached to oneanother using only a vertical attachment system.
 10. A method ofconstructing an HSM assembly, the method comprising: (a) forming aplurality of segments for the base portion of the HSM assembly; and (b)vertically stacking the segments.
 11. The method of claim 10, whereinthe plurality of segments are formed in a single form.
 12. The method ofclaim 11, wherein the first segment is poured and allowed to harden, andthe second segment is poured on the hardened first segment.
 13. Themethod of claim 11, wherein the second segment is allowed to harden, andthe third segment is poured on the hardened second segment.
 14. Themethod of claim 11, wherein the plurality of segments include bondbreakers between adjacent segments in the form.
 15. The method of claim10, further comprising vertically attaching adjacent segments.
 16. Themethod of claim 15, wherein the method does not include horizontallyattaching adjacent segments.
 17. The method of claim 10, wherein thebase portion includes at least first and second segments.
 18. The methodof claim 10, wherein the base portion includes at least first, second,and third segments.
 19. The method of claim 10, wherein the plurality ofsegments are substantially similar in at least one of size, shape, andweight.
 20. The method of claim 10, wherein the plurality of segmentsare stacked using a single lifting fixture.